1. Related Application
This application claims the benefit of U.S. provisional application Serial No. 60/300,791 filed Jun. 25, 2001, the disclosure of which is incorporated in its entirety herein by reference.
2. Field of the Invention
This invention relates to pollutant abatement generally, and more particularly to a method and apparatus for abating hydrocarbons, volatile organic compounds exhausted by a turbine or other internal combustion engine and solid wastes.
3. Description of the Prior Art
Air quality has been an increasing public concern over the past half century. In that time, the scientific community has worked to improve its understanding of the origins of pollutants that predominate in the air of most major cities in the United States. An increasing amount of this air pollution can be attributed to the release of hydrocarbons and other volatile organic compounds (VOC""s). As a result, it has become increasingly important to control and reduce the amount of these toxins that are released into the atmosphere. To that end, regulatory authorities have required that VOC""s and other volatile hydrocarbons that are hazardous to the health of humans and other organisms, be treated so as to become products that are more environmentally acceptable than their original components.
The most familiar volatile compound reduction technique is the control of fuel vaporization by vapor recovery techniques first used on automobiles and currently used on gasoline stations located in nonobtainment areas. As a result, the steady increase in releases of these compounds has leveled off and in some areas has declined.
Manufacturing sites are primarily responsible for the release of VOC""s and other hydrocarbons. Unfortunately, solvent vaporization and hydrocarbon byproducts are key to many manufacturing processes that are critical to everyday life. The manufacture of everyday consumer products result in the atmospheric release of substantial amounts of organic compounds including pentane, ethanol, methanol, and ethyl acetate, among others. While the control of these VOC""s is essential to the safety of the environment, a cost effective means for control of these compounds remains a struggle within the always competitive manufacturing industry.
Also in common use today, is the thermal oxidizer. This method allows volatile solvents to be released in amounts generally less than a few thousand parts per million into the plant air system. This air is then selectively collected and fed into a combustion chamber where it is mixed with enough natural gas to sustain combustion. This mixture is then ignited so as to incinerate the volatile solvent as well as the natural gas and to thereby produce carbon dioxide and water vapor. These thermal oxidizers are complicated devices which represent a huge capital expense and the operating costs of which typically increase the yearly energy cost in excess of 25%.
Previous control systems have controlled the amount of added fuel such as natural gas, propane, diesel fuel and the like, which is fed to the thermal oxidizer. Previous control systems have similarly controlled the amount of air fed to the thermal oxidizer which can act to control or regulate VOC emissions. Therefore, when demand is low the fuel and air fed to the thermal oxidizer is maintained at a relatively high level so as to insure VOC thermal oxidation. Such control systems result in a substantial amount of energy being wasted by exhausting hot flue gases to the atmosphere. Moreover, previous systems utilized very severe conditions which often involved unneeded combustion, which combustion itself often resulted in unnecessary air pollution.
In certain solid waste incinerators such as U.S. Pat. Nos. 3,530,807 and 3,548,761 to Zalman, the temperature in the combustion chamber is used to control the amount of fuel fed to the incinerator. In others, such as the inventor""s own U.S. Pat. No. 5,215,018, a controlled feed of gaseous materials are sent to a thermal oxidizer for cost effective thermal oxidation, as well as the creation of added heat used for secondary purposes.
Another current control technique uses solvent recovery that pass the air from the plant through an activated charcoal filter. In this method the charcoal may be periodically heated driving off highly concentrated volatile compounds into a chilled condensing system. The output is a liquid organic compound which may or may not require hazardous waste treatment. As can be expected, the costs of such an operation are significantly more expensive than a thermal oxidizer system, and thus, such a system is less attractive for the typical industrial business.
Accordingly, an efficient and cost effective device and method for the destruction of hydrocarbons and other VOC""s remains.
The present invention relates to a co-generation system for abating solid wastes, hydrocarbons and other volatile organic compounds (VOC""s) exhausted by a turbine or other internal combustion engine doing useful work. The present invention may also be utilized in a factory setting to generate power thereby reducing the overall manufacturing or industrial costs. The present invention may also neutralize exhaust to a non-toxic state by incinerating it in a secondary abatement chamber. Other unrelated pollutants such as solid waste, may be added to the abatement chamber for neutralization. The abatement chamber may also be equipped with a special catalyst to more efficiently destroy VOC""s. A gas turbine may also be used for added heat transfer to the abatement chamber. In the present invention, the abatement chamber is supplied by supplementary fuel and air inputs controlled by a computer that receives sensor inputs to achieve the requisite heat ranges necessary to convert the exhaust and VOC""s to non-toxic substances. Additionally, the present invention may transport the exhaust from the abatement chamber directly into a Stirling cycle engine to generate additional electricity as well as utilize exhaust from the Stirling engine to improve overall thermal efficiencies. The heat generated by the abatement chamber and/or the Stirling cycle engine can be used for useful work as well.
The primary advantage to this system is to use the combination of the turbine and the Stirling cycle engine to produce heat and energy which is used to help neutralize pollutants including VOC""s and solid waste, while also recycling the heat generated by the Stirling cycle engine and the supplementary fuel and VOC""s to generate heat and electricity for useful work.
Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.